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Many scientific disciplines are now data and information driven, and new scientific knowledge is often gained by scientists putting together data analysis and knowledge discovery " pipelines ". A related trend is that more and more scientific communities realize the benefits of sharing their data and computational services, and are thus contributing to a(More)
Most scientists conduct analyses and run models in several different software and hardware environments, mentally coordinating the export and import of data from one environment to another. The Kepler scientific workflow system provides domain scientists with an easy-to-use yet powerful system for capturing scientific workflows (SWFs). SWFs are a(More)
The MIX mediator system, MIX<italic>m</italic>, is developed as part of the MIX Project at the San Diego Supercomputer Center, and the University of California, San Diego.<supscrpt>1</supscrpt> MIX<italic>m</italic> uses XML as the common model for data exchange. Mediator views are expressed in XMAS (<italic>XML Matching And Structuring Language</italic>),(More)
We study the problem of rewriting queries using views in the presence of access patterns, integrity constraints, disjunction, and negation. We provide asymptotically optimal algorithms for finding minimal containing and maximal contained rewritings and for deciding whether an exact rewriting exists. We show that rewriting queries using views in this case(More)
| The closely related research areas management of semistructured data and languages for querying the Web have recently attracted a lot of interest. We argue that languages supporting deduction and object-orientation dood languages are particularly suited in this context: Object-orientation provides a exible common data model for combining information from(More)
Recent years have seen a dramatic increase in research and development of scientific workflow systems. These systems promise to make scientists more productive by automating data-driven and compute-intensive analyses. Despite many early achievements, the long-term success of scientific workflow technology critically depends on making these systems useable(More)
The XML Stream Machine (XSM) system is a novel XQuery processing paradigm that is tuned to the eecient processing of sequentially accessed XML data (streams). The system compiles a given XQuery into an XSM, which is an XML stream transducer, i.e., an abstract device that takes as input one or more XML data streams and produces one or more output streams,(More)
SUMMARY The first Provenance Challenge was set up in order to provide a forum for the community to understand the capabilities of different provenance systems and the expressiveness of their provenance representations. To this end, a Functional Magnetic Resonance Imaging workflow was defined, which participants had to either simulate or run in order to(More)
The tools used to analyze scientific data are often distinct from those used to archive, retrieve, and query data. A scientific workflow environment, however, allows one to seamlessly combine these functions within the same application. This increase in capability is accompanied by an increase in complexity, especially in workflow tools like Kepler, which(More)